Security is a major concern in data communication. One means of securing data communications is encryption, wherein the data is transformed utilizing a cryptographic algorithm (encrypted) into an unrecognizable form before transfer and then transformed using a corresponding cryptographic algorithm (decrypted) back into its original form by the intended recipient by means available only to the recipient or to a limited number of intended parties. The data is thereby rendered undiscoverable by unintended parties.
In securing data communication over an open network that is not confined to a locally secured network, hardware inline encryption devices may be utilized to encrypt the data communicated over the open network. Such devices may include Internet Protocol Security (IPSec) encryption devices which utilize the IPSec protocol suite. These encryption devices may have security associations that require fixed (unchanging) internet protocol (IP) addresses in order to be correctly identified when communicating with other encryption devices. The utilization of such encryption devices provides the potential for an exceptionally high level of security in network communications.
It would be advantageous to provide such a high level of security in communications involving handheld wireless communication devices such as mobile phones or personal digital assistants (PDAs.) These handheld devices typically utilize wireless networks that are only intermittently connected and require the utilization of dynamic internet protocol (IP) addresses for data communication. For this reason, it has not been possible to utilize in such a network a hardware inline network encryptor such as an IPSec encryption device or any other encryption device that requires the use of fixed IP addresses. A means is therefore desired for employing fixed IP address based encryption devices in a dynamic IP address based communication environment.